JP7276243B2 - battery pack - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery pack having excellent fire spread prevention properties.

In recent years, cordless electronic devices such as mobile phones and personal computers are becoming increasingly cordless, and the use of secondary batteries that are compact, lightweight, and have high energy density is increasing as a power source for driving these devices. Under such circumstances, lithium-ion secondary batteries with large charge/discharge capacities and high energy densities are attracting attention.

International publication WO2015/008747 JP-A-2006-339032 JP 2013-037794 A JP 2015-022848 A JP 2015-022849 A JP 2017-135077 A

As a lithium ion secondary battery, a stacked battery pack formed by stacking a plurality of lithium ion secondary battery cells has been devised. However, in a laminated lithium-ion secondary battery, the battery cells may generate heat due to heat generation due to oxidation of the electrolyte, short circuit due to deposition of metallic lithium, etc., and if heat generation occurs, A fire-spread prevention structure is required to prevent fire from spreading to other battery cells.

SUMMARY OF THE INVENTION An object of the present invention is to provide a battery pack that is excellent in preventing the spread of fire.

A battery pack according to the present invention includes a plurality of battery cells arranged in a stack, a housing for storing the battery cells, and a thermally conductive member in contact with the same side surface of each battery cell, the thermally conductive member are alternately in contact with the first inner surface of the housing and the second inner surface of the housing opposite to the first inner surface in the stacking order.

According to this configuration, the heat-conducting member that is in contact with the adjacent battery cells of the plurality of battery cells arranged in a stack is in contact with the inner side surface of the housing on the opposite side every other battery cell 10 . For example, the heat-conducting member of one battery cell contacts the first inner surface of the housing, and the heat-conducting member of an adjacent battery cell contacts the second inner surface, and so on. Therefore, when heat generation or combustion occurs in any one of the battery cells, the heat-conducting member of the adjacent battery cell is in contact with the inner surface of the housing on the opposite side of the battery cell that generated the heat. is difficult to transmit to adjacent battery cells. In addition, although the heat-conducting member of the battery cell two adjacent to the battery cell that has generated heat is in contact with the housing wall surface on the same side, the heat is transferred to the housing because the distance is one battery cell away. spread along the way. Therefore, the heat transferred is reduced. Therefore, the heat transferred from the heated battery cell to the surrounding battery cells is reduced, so that the spread of fire can be suppressed.

In the present invention, the distance from the end of the battery cell to the first inner side surface and the second inner side surface of the housing can be at least 5 mm or more, preferably 10 mm to 30 mm. If a distance of 5 mm or more, preferably 10 mm to 30 mm, can be secured from the end of the battery cell to the first inner surface and the second inner surface of the housing, return heat from the housing to the battery cell can be suppressed.

In the present invention, along with the heat-conducting member, a resin holder that sandwiches and surrounds each of the battery cells is provided. Configurations with defined extensions can be employed. With this configuration, it is possible to secure a distance from the resin holder that holds the battery cell to the left and right inner side surfaces of the housing. As a result, heat conduction from the housing can be suppressed, so that heat is less likely to be transferred to adjacent battery cells, making it possible to suppress the spread of fire.

According to the invention, the heat-conducting member comprises a first portion and a second portion substantially perpendicular to the first portion. The first portion is in contact with the battery cell, the second portion is in parallel contact with the first inner surface or the second inner surface of the housing, and the opposite end of the second portion of the heat-conducting member is in contact with the end of the battery cell. approximately coincides with the position of With this configuration, it is possible to secure a large area where the heat-conducting member is in contact with the inner surface of the housing, so that it is possible to improve the efficiency of heat transfer from the battery cells to the housing. As a result, it is possible to prevent the battery cells from becoming hot.

According to the present invention, a screw that penetrates the resin holder in the stacking direction of the battery cells is provided, and the screw extends from the end of the battery cell to the first inner surface of the housing or the second inner surface of the housing. Arranged configurations can be employed. Since the stacked structure of the battery cell unit can be fixed with screws or the like using the area from the inner wall of the housing to the end surface of the battery cell, it contributes to the miniaturization of the device.

According to the present invention, the resin holder can employ a configuration of thermosetting resin or a combination of thermoplastic resin and noncombustible material. In the case of a large-capacity cell, the temperature reaches a level of 300° C. for several minutes to several tens of minutes during thermal runaway.

According to the present invention, a configuration is adopted in which through holes are provided in the first inner surface and the second inner surface with which the heat conducting member is in contact, and in the end surface perpendicular to the first inner surface and the second inner surface. can be done. By providing an air hole in the battery chamber case, hot air can be released to the outside and the cooling efficiency can be improved.

According to the present invention, a configuration can be adopted in which the mating portion of the housing adjacent to the upper surface is arranged on the inner side surface opposite to the inner side surface with which the second portion of the heat conducting member is in contact. When the battery cells generate heat, the heat is easily transmitted to the mating portion of the housing that is close to the heated upper surface. It is possible to suppress the propagation of heat to the battery cells.

According to the present invention, the screw fixing portion for fixing the battery cell is arranged in the region between the battery cell end and the first inner surface or the second inner surface, and the heat conducting member and the screw are arranged so as to allow heat conduction. configuration can be employed. According to this configuration, the heat-conducting member and the bolt can be connected in a heat-transferable manner, so that the cooling efficiency of the battery cells can be improved.

Thus, according to the present invention, it is possible to provide a battery pack that is excellent in preventing the spread of fire.

FIG. 1 is a perspective view showing a schematic appearance of a battery pack 1A according to an embodiment of the invention. FIG. 2 is a see-through perspective view showing a schematic internal configuration of the battery pack 1A. FIG. 3 is a vertical cross-sectional view showing a schematic configuration of the stacked battery cells 10, and is a diagram showing a schematic configuration of a portion along line AA in FIG. FIG. 4 is a vertical cross-sectional view showing a schematic configuration of the stacked battery cells 10, and is an enlarged view of region B in FIG. FIG. 5 is a perspective view showing a schematic configuration of a battery pack 1B according to another embodiment. FIG. 6 is a vertical cross-sectional view showing the schematic structure of the battery pack 1B, showing the schematic structure of the portion taken along line CC of FIG.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, the Y direction may be referred to as the left-right direction, the Z direction as the up-down direction, and the X direction as the front-back direction. Also, in the following description, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

A battery pack 1A according to an embodiment will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a perspective view showing a schematic appearance of a battery pack 1A according to an embodiment of the invention. FIG. 2 is a see-through perspective view showing a schematic internal configuration of the battery pack 1A. FIG. 3 is a vertical cross-sectional view showing a schematic configuration of the stacked battery cells 10, and is a diagram showing a schematic configuration of a portion along line AA in FIG. FIG. 4 is a vertical cross-sectional view showing a schematic configuration of the stacked battery cells 10, and is an enlarged view of region B in FIG.

As shown in FIGS. 1 and 2, the battery pack 1A includes a battery chamber case 2 and a gas chamber case 4, which are hollow cubes. The exterior of the battery chamber case 2 is composed of a housing 2b. The exterior of the gas chamber case 4 is composed of a housing 4b. The battery chamber case 2, the gas chamber case 4, and the housings 2b and 4b constituting these are made of metal such as aluminum.

The inside of the battery chamber case 2 is a battery chamber 2a. A plurality of battery cell units 8 stacked in the Z direction are stored in the battery chamber 2a. The four corners of the battery cell unit 8 are integrally fixed by bolt screws 16 passing through the plurality of battery cell units 8 . The inside of the gas chamber case 4 is a gas chamber 4a. Substrates 4 d and 4 e are provided in the gas chamber case 4 .

As shown in FIGS. 3 and 4, a battery cell unit 8 including a plurality of stacked battery cells 10 is housed in a battery chamber 2a inside a housing 2b that constitutes the battery chamber case 2. As shown in FIG. The battery cell 10 is, for example, a lithium ion secondary battery cell sealed with a sealing member obtained by laminating a resin and a metal film. The battery cell unit 8 includes battery cells 10 , heat conducting members 12 and resin holders 14 . The battery cell 10 is sandwiched from above and below by the heat conducting member 12 and the resin holder 14 and surrounded.

The resin holder 14 is made of a thermosetting resin or a combination of a thermoplastic resin and a noncombustible material. When the battery cell 10 is a large-capacity cell, the temperature reaches the 300° C. level for several minutes to several tens of minutes during thermal runaway. Insulation can be maintained without causing

The resin holder 14 has extensions 14a extending from the left and right ends of the battery cell 10 to both sides thereof. The extension 14a has a width D. An end portion of the extension portion 14 a is in contact with the inner surface of the housing 2 b of the battery chamber case 2 . The extended portion 14a separates the left-right end of the battery cell 10 from the inner surface of the housing 2b by a distance D. As shown in FIG. By securing the distance to the left and right inner side surfaces of the housing 2b by the extension portion 14a, heat conduction from the housing 2b can be suppressed. Therefore, it becomes difficult for heat to be transferred to the adjacent battery cells 10, and it is possible to suppress the spread of fire.

The distance D is set to be at least 5 mm or more, more preferably 10 mm to 30 mm. The distance from the left and right ends of the battery cell 10 to the right inner surface (hereinafter referred to as the first inner surface 2c) and the left inner surface (hereinafter referred to as the second inner surface 2d) of the housing 2b is 5 mm or more, Desirably, if 10 mm to 30 mm can be secured, return heat from the housing 2b to the adjacent battery cells 10 can be suppressed.

The heat-conducting member 12 has a first portion 12a in surface contact with the upper surface of the battery cell 10 and a second portion 12b perpendicular to the first portion 12a, and has an L-shaped plate shape as a whole. The heat conducting member 12 is made of a metal having good heat conductivity, such as aluminum.

As shown in FIG. 4 and the like, in the heat conducting member 12, when the heat conducting member 12 is arranged in surface contact with the top surface of each of the plurality of battery cells 10, the left and right positions of the second portions 12b alternate in the stacking order. is different. With this configuration, the second portion 12b of the heat-conducting member 12 is formed between the first inner side surface 2c of the housing 2b and the second portion of the housing 2b, which is the surface opposite to the first inner side surface 2c. 2 are alternately in surface contact with the inner side surface 2d in the stacking order. In other words, the inner surface with which the heat conducting member 12 is in contact is changed for each battery cell 10 to be stacked. The second portion 12b may be in surface contact with the inner surface of the housing 2b with mica 18 having excellent electrical insulation and heat resistance interposed therebetween.

According to this configuration, for example, the heat-conducting member 12 of a certain battery cell 10 is in contact with the first inner side surface 2c on the right side of the housing 2b, and the heat-conducting member 12 of the adjacent battery cell 10 is in contact with the second inner side surface 2c on the left side. They are alternately arranged so as to touch the side surface 2d. Therefore, when heat generation or combustion occurs in any one of the plurality of battery cells 10 housed in the battery chamber case 2, the heat conducting member 12 of the adjacent battery cell 10 is placed on the opposite side of the housing. Since it is in contact with the inner side of the body, heat is less likely to be transferred to adjacent battery cells 10 . Also, the heat conducting member 12 of the battery cell 10 that is two adjacent to the battery cell 10 that has generated heat is in contact with the inner surface of the housing 2b on the same side, but is separated by a distance of one battery cell 10 . Therefore, the heat is diffused and reduced while being transmitted through the housing 2b, so that the heat transmitted to the battery cell 10 that is two adjacent is reduced. Therefore, the heat transferred from the battery cell 10 that has generated heat to the surrounding battery cells 10 is reduced, so that the spread of fire can be suppressed.

As described above, the heat-conducting member 12 includes a first portion 12a and a second portion 12b substantially perpendicular to the first portion 12a. The first portion 12a is in contact with the battery cell 10, and the second portion 12b is in surface contact with the first inner surface 2c or the second inner surface 2d of the housing 2b. The end of the heat-conducting member 12 opposite to the second portion 12b substantially coincides with the end of the battery cell 10 . With this configuration, a large surface of the heat conducting member 12 in contact with the inner surface of the housing 2b can be ensured, so that the efficiency of heat transfer from the battery cell 10 to the housing 2b can be improved. As a result, it is possible to prevent the battery cell 10 from becoming hot.

The battery cell unit 8 is provided with a bolt screw 16 that penetrates the resin holder 14 in the stacking direction of the battery cell unit 8 . The bolt screw 16 extends vertically from the end of the battery cell 10 to the first inner side surface 2c of the housing 2b or the second inner side surface 2d of the housing 2b, that is, in region D where the extension 14a is arranged. are arranged to extend in the direction According to this configuration, the stacked structure of the battery cell unit 8 can be fixed with screws or the like using the space from the inner surface of the housing 2b to the end of the battery cell 10, which contributes to downsizing of the device. . In addition, since the D region also has a function of absorbing external shocks and protecting the battery cells 10, it contributes to the safety of the device.

According to the present invention, a screwing portion for fixing the housing 2b is arranged in the region between the end of the battery cell 10 and the first inner side surface 2c or the second inner side surface 2d. The bolt screw 16 has a rod portion 16a, and the rod portion 16a is arranged so as to pass through screw holes provided in the resin holder 14 and the heat conducting member 12 in the region D. As shown in FIG. In this manner, the heat-conducting member 12 and the bolt screw 16 are arranged so as to be heat-conducting. According to this configuration, the heat conducting member 12 and the bolt screw 16 can be connected in a heat transferable manner, so that the cooling efficiency of the battery cell 10 can be improved.

Next, a battery pack 1B according to another embodiment will be described with reference to FIGS. 5 and 6. FIG. FIG. 5 is a perspective view showing a schematic structure of another embodiment of the battery pack 1B. FIG. 6 is a vertical cross-sectional view showing the schematic structure of another embodiment of the battery pack 1B, showing the schematic structure of the portion along line CC in FIG.

As shown in FIG. 5, the battery pack 1B has a battery chamber case 2. As shown in FIG. The battery chamber case 2 includes a side surface 20a arranged in the Y direction, an end surface 20b arranged in the X direction, and an upper surface 20c arranged on the upper side in the X direction. The upper surface 20c and the side surface 20a form a joint portion 26 in which a metal plate forming the upper surface 20c is bent substantially at a right angle to cover a part of the side surface 20a. The side surface 20a and the upper surface 20c are connected by this joint portion 26, for example, by welding. A plurality of through holes 21a are provided in the side surface 20a. A plurality of through-holes 21b are provided in an end face 20b forming a substantially right angle with the side face 20a.

As shown in FIGS. 5 and 6, as the mating portion 26, a mating portion 26a arranged on the upper left of the battery chamber case 2 in the drawings and a mating portion 26b arranged on the lower right are arranged. The through hole 21a is arranged on the side surface 20a of the housing 2b with which the second portion 12b of the heat conducting member 12 is in contact. The through-hole 21a is configured to pass through the end surface of the extended portion 14a of the resin holder 14, the mica 18, and the housing 2b. The through hole 21 a is provided so as to communicate the cavity 28 formed between the resin holders 14 in the area D and the outside of the battery chamber case 2 . A through hole 21 b provided in the end face 20 b is also provided so as to communicate the cavity 28 with the outside of the battery chamber case 2 .

By providing the through holes 21a and 21b, which are air holes, in the battery chamber case 2, the hot air inside the battery chamber case 2 can be released to the outside, and the cooling efficiency can be improved. The mating portion 26a adjacent to the upper surface 20c is arranged on the inner side surface opposite to the inner side surface of the housing 2b with which the second portion 12b of the heat conducting member 12 contacts. Since the upper surface 20c is heated when the battery cell 10 generates heat, the heat is likely to propagate to the mating portion 26a adjacent to the upper surface 20c. However, by arranging the second portion 12b of the heat-conducting member 12, which is in surface contact with the housing 2b, on the opposite side of the mating portion 26a, the heat transfer to the battery cell 10 can be suppressed.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. Needless to say, it is included within the scope.

1 battery pack 2 battery chamber case 2a battery chamber 2b housing 2c first inner surface 2d second inner surface 4 gas chamber case 4a gas chamber 4b housing 4c partition plate 4d, 4e substrate 8 battery cell unit 10 battery cell 12 heat conduction Member 12a First portion 12b Second portion 14 Resin holder 14a Extension portion 16 Bolt screw 16a Rod portion 18 Mica 20a Side surface 20b End surface 20c Upper surface 21a, 21b Through holes 26, 26a, 26b Joint portion 28 Cavity

Claims (8)

a plurality of battery cells arranged in a stack;
a housing that stores the battery cell;
and a thermally conductive member in contact with the same side surface of each of the battery cells,
each of the heat-conducting members is alternately in contact with the first inner surface of the housing and the second inner surface of the housing opposite to the first inner surface in the order of stacking;
The heat conducting member comprises a first portion and a second portion substantially perpendicular to the first portion,
The first portion contacts the battery cell, the second portion contacts the first inner surface or the second inner surface of the housing in parallel,
The battery pack, wherein the mating portion of the housing adjacent to the upper surface is arranged on the inner side surface opposite to the inner side surface with which the second portion of the heat conducting member is in contact. 2. The battery pack according to claim 1, wherein the distance from the end of the battery cell to the first inner side and the second inner side of the housing is 10 mm to 30 mm. Along with the heat-conducting member, a resin holder that sandwiches each of the battery cells and surrounds the periphery of the battery cells,
3. The battery pack according to claim 1, wherein the resin holder has extensions defining distances from the battery cell end to the first inner side surface and the second inner side surface of the housing. 4. The battery pack according to claim 3, wherein the opposite end of said second portion of said heat-conducting member substantially coincides with the position of the end of said battery cell. a screw penetrating the resin holder in the stacking direction of the battery cells,
4. The battery pack according to claim 3, wherein the screw is arranged between the battery cell end and the first inner surface of the housing or the second inner surface of the housing. 4. The battery pack according to claim 3, wherein the resin holder is made of a thermosetting resin or a combination of a thermoplastic resin and a noncombustible material. 2. The heat-conducting member according to claim 1, wherein through-holes are provided in the first inner surface and the second inner surface with which the heat-conducting member is in contact, and in the end surface perpendicular to the first inner surface and the second inner surface. battery pack. A screw fixing portion for fixing the battery cell is arranged in a region between the battery cell end and the first inner side surface or the second inner side surface, and the heat conducting member and the screw are arranged so as to allow heat conduction. The battery pack of claim 1, characterized in that.

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